arch/m68k/include/asm/processor.h

   1 /*
   2  * include/asm-m68k/processor.h
   3  *
   4  * Copyright (C) 1995 Hamish Macdonald
   5  */
   6
   7 #ifndef __ASM_M68K_PROCESSOR_H
   8 #define __ASM_M68K_PROCESSOR_H
   9
  10 /*
  11  * Default implementation of macro that returns current
  12  * instruction pointer ("program counter").
  13  */
  14 #define current_text_addr() ({ __label__ _l; _l: &&_l;})
  15
  16 #include <linux/thread_info.h>
  17 #include <asm/segment.h>
  18 #include <asm/fpu.h>
  19 #include <asm/ptrace.h>
  20
  21 static inline unsigned long rdusp(void)
  22 {
  23 #ifdef CONFIG_COLDFIRE_SW_A7
  24         extern unsigned int sw_usp;
  25         return sw_usp;
  26 #else
  27         register unsigned long usp __asm__("a0");
  28         /* move %usp,%a0 */
  29         __asm__ __volatile__(".word 0x4e68" : "=a" (usp));
  30         return usp;
  31 #endif
  32 }
  33
  34 static inline void wrusp(unsigned long usp)
  35 {
  36 #ifdef CONFIG_COLDFIRE_SW_A7
  37         extern unsigned int sw_usp;
  38         sw_usp = usp;
  39 #else
  40         register unsigned long a0 __asm__("a0") = usp;
  41         /* move %a0,%usp */
  42         __asm__ __volatile__(".word 0x4e60" : : "a" (a0) );
  43 #endif
  44 }
  45
  46 /*
  47  * User space process size: 3.75GB. This is hardcoded into a few places,
  48  * so don't change it unless you know what you are doing.
  49  */
  50 #ifdef CONFIG_MMU
  51 #if defined(CONFIG_COLDFIRE)
  52 #define TASK_SIZE       (0xC0000000UL)
  53 #elif defined(CONFIG_SUN3)
  54 #define TASK_SIZE       (0x0E000000UL)
  55 #else
  56 #define TASK_SIZE       (0xF0000000UL)
  57 #endif
  58 #else
  59 #define TASK_SIZE       (0xFFFFFFFFUL)
  60 #endif
  61
  62 #ifdef __KERNEL__
  63 #define STACK_TOP       TASK_SIZE
  64 #define STACK_TOP_MAX   STACK_TOP
  65 #endif
  66
  67 /* This decides where the kernel will search for a free chunk of vm
  68  * space during mmap's.
  69  */
  70 #ifdef CONFIG_MMU
  71 #if defined(CONFIG_COLDFIRE)
  72 #define TASK_UNMAPPED_BASE      0x60000000UL
  73 #elif defined(CONFIG_SUN3)
  74 #define TASK_UNMAPPED_BASE      0x0A000000UL
  75 #else
  76 #define TASK_UNMAPPED_BASE      0xC0000000UL
  77 #endif
  78 #define TASK_UNMAPPED_ALIGN(addr, off)  PAGE_ALIGN(addr)
  79 #else
  80 #define TASK_UNMAPPED_BASE      0
  81 #endif
  82
  83 struct thread_struct {
  84         unsigned long  ksp;             /* kernel stack pointer */
  85         unsigned long  usp;             /* user stack pointer */
  86         unsigned short sr;              /* saved status register */
  87         unsigned short fs;              /* saved fs (sfc, dfc) */
  88         unsigned long  crp[2];          /* cpu root pointer */
  89         unsigned long  esp0;            /* points to SR of stack frame */
  90         unsigned long  faddr;           /* info about last fault */
  91         int            signo, code;
  92         unsigned long  fp[8*3];
  93         unsigned long  fpcntl[3];       /* fp control regs */
  94         unsigned char  fpstate[FPSTATESIZE];  /* floating point state */
  95 };
  96
  97 #define INIT_THREAD  {                                                  \
  98         .ksp    = sizeof(init_stack) + (unsigned long) init_stack,      \
  99         .sr     = PS_S,                                                 \
 100         .fs     = __KERNEL_DS,                                          \
 101 }
 102
 103 #ifdef CONFIG_MMU
 104 /*
 105  * Do necessary setup to start up a newly executed thread.
 106  */
 107 static inline void start_thread(struct pt_regs * regs, unsigned long pc,
 108                                 unsigned long usp)
 109 {
 110         regs->pc = pc;
 111         regs->sr &= ~0x2000;
 112         wrusp(usp);
 113 }
 114
 115 extern int handle_kernel_fault(struct pt_regs *regs);
 116
 117 #else
 118
 119 /*
 120  * Coldfire stacks need to be re-aligned on trap exit, conventional
 121  * 68k can handle this case cleanly.
 122  */
 123 #ifdef CONFIG_COLDFIRE
 124 #define reformat(_regs)         do { (_regs)->format = 0x4; } while(0)
 125 #else
 126 #define reformat(_regs)         do { } while (0)
 127 #endif
 128
 129 #define start_thread(_regs, _pc, _usp)                  \
 130 do {                                                    \
 131         (_regs)->pc = (_pc);                            \
 132         ((struct switch_stack *)(_regs))[-1].a6 = 0;    \
 133         reformat(_regs);                                \
 134         if (current->mm)                                \
 135                 (_regs)->d5 = current->mm->start_data;  \
 136         (_regs)->sr &= ~0x2000;                         \
 137         wrusp(_usp);                                    \
 138 } while(0)
 139
 140 static inline  int handle_kernel_fault(struct pt_regs *regs)
 141 {
 142         /* Any fault in kernel is fatal on non-mmu */
 143         return 0;
 144 }
 145
 146 #endif
 147
 148 /* Forward declaration, a strange C thing */
 149 struct task_struct;
 150
 151 /* Free all resources held by a thread. */
 152 static inline void release_thread(struct task_struct *dead_task)
 153 {
 154 }
 155
 156 /* Prepare to copy thread state - unlazy all lazy status */
 157 #define prepare_to_copy(tsk)    do { } while (0)
 158
 159 extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 160
 161 /*
 162  * Free current thread data structures etc..
 163  */
 164 static inline void exit_thread(void)
 165 {
 166 }
 167
 168 extern unsigned long thread_saved_pc(struct task_struct *tsk);
 169
 170 unsigned long get_wchan(struct task_struct *p);
 171
 172 #define KSTK_EIP(tsk)   \
 173     ({                  \
 174         unsigned long eip = 0;   \
 175         if ((tsk)->thread.esp0 > PAGE_SIZE && \
 176             (virt_addr_valid((tsk)->thread.esp0))) \
 177               eip = ((struct pt_regs *) (tsk)->thread.esp0)->pc; \
 178         eip; })
 179 #define KSTK_ESP(tsk)   ((tsk) == current ? rdusp() : (tsk)->thread.usp)
 180
 181 #define task_pt_regs(tsk)       ((struct pt_regs *) ((tsk)->thread.esp0))
 182
 183 #define cpu_relax()     barrier()
 184
 185 #endif